225 THE LOWER LIMB 226 SURFACE MARKINGS 1. bones & joints • Superior anterior iliac spine • Greater tuberosity [trochander] of humerus A hand’s breadth below the iliac crest, easily palpable with the hip adducted, so thet the hip abductors [gluteus minimus, gluteus medius & tensor fasciae latae] are relaxed. • Ischial tuberosity The body weight is put on it when the subjects sits. Is covered by the gluteus minimus which slips away when sitting. • Patella Is freely mobile from side to side • Condyles of femur • Condyles of tibia • Adductor tubercle of femur Is the first bony prominence met when the hand runs down the medial side of thigh. • Knee joint line • Tibial tuberosity A bony prominence 6cm below the knee where the patellar ligament of rectus femoris inserts. • Head of fibula Is easily palpable below the lateral epicondyle of tibia • Shaft of tibia Its anterior surface is subcutaneous • Medial malleolus • Fibula Is subcutaneous on its distal 7-10cm. • Lateral malleolus Lies inferiorly than the medial malleolus • Head of talus Is the block of bone felt in front of malleoli • Tuberosity of the navicular A bony prominence 3cm in front of medial malleolus [insertion point of tibialis anterior] • Base of 5th metacarpal At the lateral border of the foot, the insertion point of peroneus brevis • Calcaneus • Peroneum tubercle, 2.5 cm below lateral malleolus • Sustentaculum tali, 2.5 cm below medial malleolus 2.BURSAE Some bony prominences of the lower limb have an overlying bursa [risk of inflammation leading to considerable distension]. • Over ischial tuberosity 227 Is caused by too much sitting [weaver’s bottom] • In front of patella Prolonged forward kneeling [housemaid’s knee], causing prepatellar bursitis • Infrapatellar bursitis Inflammation of the bursa over the ligamentum patellae, caused be more erect kneeling • Bursitis over Achiles tendon, navicular tuberosity or over the phalanges Is caused by tight shoes • Bunion A thickened bursa on the inner aspect of the 1st metatarsal head, usually associated with hallux valgus deformity. 3. LIMB MEASUREMENTS • REAL SHORTENING OF LIMB Actual loss of bone length. The legs are put into exactly the same position and the distance between anterior superior iliac spine and medial malleolus is measured bilaterally. • APPARENT SHORTENING May be due to fixed deformity of the limb. The limbs are positioned parallel [as erect] and the distance between the umbilicus and medial malleolus is measured. Apparent shortening is usually more than the real; if it is less, this can only be explained by an ankylosed hip in the abducted position. • WHERE IS THE SHORTENING LOCATED? 1. HIP a. Nelaton’s line: line joining superior anterior iliac spine and ischial tuberosity. It should lie above the greater trochanter b. Distance between superior anterior iliac spine and greater trochanter c. Bryant’s triangle: the distance between a perpendicular from the superior anterior iliac spine and the greater trochanter [a 90 triangle] 2. FEMUR Distance from superior anterior iliac spine to the knee joint. Distance from greater trochanter to the knee joint. 3. TIBIA Distance of a line joining the knee joint to the medial malleolus 4. MUSCLES & TENDONS • QUADRICEPS FEMORIS The prominent anterior bulk mass of the thigh inserting into the patella [more on the medial than lateral side] • SARTORIUS The hip is put flexed and externally rotated. Extends from the superior anterior iliac spine to the medial border of the upper tibia, forming the lateral border of femoral triangle. • GLUTEUS MAXIMUS 228 The bulk of buttock. More prominent with the hip extended. • GLUTEUS MINIMUS & MEDIUS [HIP ADDUCTORS] They tighten and become prominent in resistent adduction and abduction of the hip • TENDONS AROUND THE KNEE Laterally: 1. Biceps femoris tendon, inserting into the head of fibula 2. Iliotibial tract [tensor fasciae latae]: 2.5cm in front of lateral tibial condyle 3. Vastus lateralis tendon Medially: 1. Semitendinous [laterally] 2. Semimembranosus 3. Gracilis [medially] 4. Sartorius • ACHILLES TENDON Fusion of the tendons of the gastrocnemius and soleus muscle, inserting into the calcaneus. • ANKLE TENDONS IN FRONT OF MEDIAL MALLEOLUS • Tibialis anterior tendon [inserts into the navicular and base of 1st metatarsal], medially • Extensor hallucis longus tendon [middle] • Extensor digitorum longus tendon [laterally] TENDONS BELOW THE LATERAL MALLEOLUS • Peroneus longus • Peroneus brevis TENDONS BEHIND THE MEDIAL MALLEOLUS From medial to lateral, under the flexor retinaculum, pass: 1. Tibialis posterior 2. Flexor digitorum longus posterior tibial artery and venae commitantes tibial nerve 3. Flexor hallucis longus 4. Achilles tendon 5. VESSELS • FEMORAL ARTERY Passes below the inguinal ligament at the mid-inguinal point [half the distance between superior anterior iliac spine and pubic symphysis]; it then lies [SFA] in a line towards the adductor tubercle with the hip somewhat flexed and externally rotated. • FEMORAL NERVE: a finger’s breadth laterally • FEMORAL VEIN Immediately posteromedially to the artery • POPLITEAL ARTERY Inside the popliteal fossa, with the knee flexed and the fingers pressing firmly towards the back of femur. • DORSALIS PEDIS [absent in 14%] On the dorsum of the foot, between the tendons of extensor hallucis longus and extensor digitorum. 229 • POSTERIOR TIBIAL ARTERY [absent in 5%] A finger’s breadth posteroinferiorly to the medial malleolus • LONG SAPHENOUS VEIN Always present in front of medial malleolus. Anterior to it lies the saphenous nerve. The saphenofemoral junction in the groin lies 2.5cm below the inguinal ligament and 2.5 cm medial to femoral pulse [one finger lateral to the pubic tubercle] • SHORT SAPHENOUS VEIN Behind the lateral malleolus, ascending halfway between the edge of fibula and the Achilles tendon. Posterolaterally to it lies the sural nerve. 6. NERVES • FEMORAL NERVE Emerges below the inguinal ligament, a finger’s breadth lateral to the femoral pulse. Its course is only 5 cm, branching immediately into terminal branches for the quadriceps femoris. • SCIATIC NERVE Commences at the midpoint between superior anterior iliac spine and ischial tuberosity. Curves outwards and downwards, passing at the midpoint between the greater trochanter and ischial tuberosity. Continues vertically downwards, lying on the midline of the posterior thigh surface. Above the true popliteal fossa it divides into the tibial nerve [medially] and the common peroneal nerve [lateral] • COMMON PERONEAL NERVE. It winds round the neck of fibula, lying superficially. Injury there will be followed by foot drop. It splits into superficial and deep peroneal nerve. 230 BONES 1. OS INNOMINATUM [INNOMINATE BONE] Fusion of ilium, ischium and pubic bone. 2. THE FEMUR Is the longest bone of the body [45cm, the same length as vas deferens, spinal cord, thoracic duct, distance from incisor teeth to cardia] • HEAD Comprises 2/3rds of a sphere, facing upward, medially and forwards. Is covered with cartilage, except the central fovea where the ligamentum teres is attached. Blood supply to the head is derived from: a. vessels traveling up from the diaphysis b. vessels from the hip synovial capsule c. vessels from ligamentum teres • NECK 5cm long, forming a 125 angle to the shaft. • Greater trochanter [laterally], the insertion point of gluteus minimus ans medius. • Intertrochanteric line [anteriorly] • Lesser trochanter [medially], insertion of iliopsoas • Trochanteric crest [posteriorly] FRACTURES OF THE NECK OF FEMUR • Subcapital [beneath the head] • Cervical [at the midpoint] • Basal • Pertrochanteric Neck fractures interrupt the blood supply from the diaphysis; if the retinacula is also torn, the result will be avascular necrosis of the head. This is more common in fractures closer to the head while it almost never happens with pertrochanteric fractures. • SHAFT Cylindric at its middle, flattens posteriorly at its extremities • Linea aspera [a strong posterior crest] • Superiorly • gluteal tuberosity [laterally] • spiral line • Inferiorly • lateral supracondylar ridge • medial supracondylar ridge, leading to • Adductor tubercle • Popliteal surface between the two supracondylar ridges 231 • The bones of the upper lower limb [anterior view] 232 • Two condyles [lateral & medial] • intercondylar notch [posteriorly] • articular surface for the patella [anteriorly] FRACTURES OF THE SHAFT Are accompanied by considerable shortening due the action of the strong surrounding muscles. • Proximal fractures The proximal segment is flexed by iliopsoas and abducted by gluteus minimus-medius, while the distal segment is pulled medially by the adductor muscles. Reduction should be performed initially by powerful traction followed by proper manipulation. • Distal fractures [rare] The distal part is tilted backwards by the action of gastrocnemius. The popliteal artery may thus be torn. 3. THE PATELLA A sesamoid bone within the tendinous expansion of quadriceps femoris, which continues distally as the ligamentum patellae. On its posterior surface [which has 2 facets] the patella is covered by cartilage, articulating with the patellar surface of the two femoral condyles. Lateral dislocation of the patella is restricteed because of: a. medial insertion of vastus medialis tendon into the patella b. prominent articular surface of lateral condyle The patella may fracture by violent quadriceps contraction, in which case the tear might extend proximally [into the tendon expansion] or distally [into the ligamentum patellae]; the upper fragment